This invention relates to a machine for manufacturing flat envelopes from a heat sealable material, and for filling, sealing and conveying such envelopes.
Past studies have led to the provision of machines wherein the formation of the envelopes, consecutively to one another along a heat sealable web folded up lengthwise, and the subsequent filling and sealing of the envelopes, are performed with an intermittent processing method owing to the fact that a majority of the members participating in such a formation perform a reciprocating motion. In these machines, which will be termed "reciprocating" for brevity, the main manipulations and handling steps on the heat sealable web, and accordingly on the envelopes obtained therefrom, are carried out with the web held stationary. A high product quality is achieved, thanks especially to the stability and reliability of the heat sealed seems thus obtained; however, the hourly output of the reciprocating machines is not so satisfactory, due to the slow rate of their envelope forming cycle.
Other machines, also provided by previous studies, process the heat sealable web and envelopes while moving or on-the-fly, and afford a higher production output, but at the expense of the resulting product quality, due to failure of the sealed seams.
The design is, moreover, such as to present the usual problem of interrupting the production cycle every time that the coil or roll of heat sealable web is exhausted and a fresh one is to be installed.